1. Field of the Invention
The present invention relates to an electric conductivity-measuring cell used for measuring an electric conductivity of chemical substances, which are used in a production of semiconductors and are gaseous at normal temperature and pressure. The measuring cell can operate under condition of liquefied gases and for a control of water quality of industrial water, water supplied for a boiler, various kinds of washing water and the like, and in particular to an electric conductivity-measuring cell suitable for a measurement of an electric conductivity of liquids, which exist under high-temperature and high-pressure conditions, such as a primary cooling water in a nuclear power plant.
2. Description of the Prior Art
High-purity halogen gases, inorganic hydrides, such as hydrogen halide gases, and the like have been used as dry etching gases in the production of semiconductors and various kinds of gas, such as SiH.sub.4, Si.sub.2 H.sub.6 and SiH.sub.2 Cl.sub.2, have been used in the formation of thin films of Si, SiO.sub.2, Si.sub.3 N.sub.4 and the like. If such gases have a remarkably very small quantity (for example a ppb-level) of impurities contained in these gases, a bad influence upon a manufacturing process of LSI and the like by these impurities is increased as a circuit pattern is reduced to very find details and also a gas piping system itself can be seriously influenced. So, it has been desired in the industry to accurately measure any concentration of the impurities at a ppb-level and to monitor them.
In addition, various kinds of impurities, such as corrosion products by an electrolysis, are formed by an operation of a reactor in reactor-cooling water circulating through a primary cooling system of a boiling water reactor. In particular, when electric conductivity is increased with an increase of electrolyzed components, a rate of corrosion of structures in such a system is rapidly increased and corrosion products are further radioactivated by neutrons to increase a radioactive level within the system while electrolytic impurities are settled on a surface of fuel rods to hinder a smooth thermal conductance. As a result, the operating efficiency of the reactor is reduced, so that the primary cooling water must be suitably refined to a high purity level or newly replenished to be controlled so that a constant water quality may be always kept. In particular, the control of the electric conductivity as an index of the quantity of said electrolyzed components is an important item for the control of water quality of the primary cooling water.